Allow loopback in vcr_config so --block-network works on Windows

Windows has no AF_UNIX socketpair(), so socket.socketpair() falls back
to connecting a real loopback socket. asyncio's ProactorEventLoop uses
exactly that call to build its self-pipe, so pytest-recording's network
guard (--block-network, set in addopts) makes asyncio.run() itself
raise "Network is disabled" before any async test can run, failing the
whole suite on setup rather than in the test bodies.

allowed_hosts already matches VCR's own host allowlist mechanism, so
letting 127.0.0.1 through here re-enables loop construction without
weakening the guard: provider endpoints stay blocked, only loopback is
let through.

Fixes typesafe-ai#44.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: rmnvg

tests/conftest.py

@@ -120,6 +120,12 @@ def vcr_config() -> dict[str, Any]:
         VCR configuration passed to `VCR.use_cassettes`.
     """
     return {
+        # --block-network (see addopts) blocks every socket connect, which on Windows
+        # takes the suite down before a single test runs: there the ProactorEventLoop
+        # builds its self-pipe with socket.socketpair(), whose Windows fallback
+        # connects to 127.0.0.1, so asyncio.run() itself raises "Network is disabled".
+        # Loopback is the only host let back through; provider endpoints stay blocked.
+        "allowed_hosts": ["127.0.0.1"],
         # The registered JSON serializer keeps HTTP bodies as nested objects, so the
         # cassette diffs like its payloads instead of escaped string literals.
         "serializer": "json",